The specifications for the GSLV-3 are similar to a Titan 3 launcher with a centaur upper stage.

It is therefore reasonable to expect that the GSLV could put at least 15 tons in LEO. I would not be surprised if they eventually put 20 tons in LEO.

The GSLV-4 (essentially a double GSLV-3) would be able to put between 40-45 tons in orbit. It would be possible to launch a lunar expedition with 2 GSLV-4 lauches (one for the TLI stage and one for the orbiter+ lander).

The speculation is that it will be able to launch 10 tons to LEO and 4 tons to GSO. But I am really doubting if a rocket with this kind of thrust would have such minimal capabilities.

I compared every stage to the Ariane-5 ECA and really GSLV-MK3 outdid it in thrust. Ariane has a capability of 6-7 to GSO and about 15-18 tons to LEO.

So I really think that GSLV- Mk 3 would be a heavy lifter like the Ariane-5 and Angara. So please post the possible capability that you could think !!!!!!

My thinking is that its reduced capability is mainly due to the low burn time of the core stage !!!!!!! I

These numbers do not add up. The "2400,000 kg" Stage Zero GLOW is obviously in error. If it is supposed to be "240,000 kg", then that doesn't match the "554,301 lb" (251,384 kg) number.

The "7,698 kN" Stage Zero thrust may be correct for liftoff, but a much lower average thrust, something like 4,750 kN, is required for the burn time to match the propellant and specific impulse numbers.

The 1,600 kN Stage One thrust seems too high to me. Available propellant, burn time, and specific impulse suggests something closer to 1,400 kN, which is more in line with current Vikas capabilities.

I suspect that the dry mass of the Cryo stage would have to be less than the suggested 5 tonnes in order to achieve the reported 4 tonnes payload to GTO. I have to put it at 4 tonnes in my spreadsheet to get close to the required delta-v. With a 5 tonne dry mass, I can't even get a 3 tonne payload to GTO!

If I assume a 4 tonne dry Cryo stage mass, I can get 12.5-13 tonnes to LEO on my spreadsheet model, but this doesn't take into account the very low T/W ratio that the upper stage would provide. (Obviously the LEO payload would only be 11.5-12 tonnes for a 5 tonne dry mass Cryo stage.) A highly lofted trajectory would be needed for a heavy LEO payload. The real capability of this launch vehicle will depend heavily on its upper stage, which is providing more than 50% of the delta-v.

One possibility is that the reported 10 tonnes payload is for sun synchronous LEO.

As it stands, GSLV Mk3 looks to be roughly equivalent to a Titan 3C, LEO wise, but with better GTO performance due to the use of an LH2 upper stage.

The speculation is that it will be able to launch 10 tons to LEO and 4 tons to GSO. But I am really doubting if a rocket with this kind of thrust would have such minimal capabilities.

I compared every stage to the Ariane-5 ECA and really GSLV-MK3 outdid it in thrust. Ariane has a capability of 6-7 to GSO and about 15-18 tons to LEO.

So I really think that GSLV- Mk 3 would be a heavy lifter like the Ariane-5 and Angara. So please post the possible capability that you could think !!!!!!

My thinking is that its reduced capability is mainly due to the low burn time of the core stage !!!!!!! I

These numbers do not add up. The "2400,000 kg" Stage Zero GLOW is obviously in error. If it is supposed to be "240,000 kg", then that doesn't match the "554,301 lb" (251,384 kg) number.

The "7,698 kN" Stage Zero thrust may be correct for liftoff, but a much lower average thrust, something like 4,750 kN, is required for the burn time to match the propellant and specific impulse numbers.

The 1,600 kN Stage One thrust seems too high to me. Available propellant, burn time, and specific impulse suggests something closer to 1,400 kN, which is more in line with current Vikas capabilities.

I suspect that the dry mass of the Cryo stage would have to be less than the suggested 5 tonnes in order to achieve the reported 4 tonnes payload to GTO. I have to put it at 4 tonnes in my spreadsheet to get close to the required delta-v. With a 5 tonne dry mass, I can't even get a 3 tonne payload to GTO!

If I assume a 4 tonne dry Cryo stage mass, I can get 12.5-13 tonnes to LEO on my spreadsheet model, but this doesn't take into account the very low T/W ratio that the upper stage would provide. (Obviously the LEO payload would only be 11.5-12 tonnes for a 5 tonne dry mass Cryo stage.) A highly lofted trajectory would be needed for a heavy LEO payload. The real capability of this launch vehicle will depend heavily on its upper stage, which is providing more than 50% of the delta-v.

One possibility is that the reported 10 tonnes payload is for sun synchronous LEO.

As it stands, GSLV Mk3 looks to be roughly equivalent to a Titan 3C, LEO wise, but with better GTO performance due to the use of an LH2 upper stage.

- Ed Kyle

But Ariane-5 ECA carries 238 metric tons of propellant in the booster stage and yet gets about 6500kN of average thrust.

But Ariane-5 ECA carries 238 metric tons of propellant in the booster stage and yet gets about 6500kN of average thrust.

That's not the average thrust, that's probably the peak or liftoff thrust. The thrust is going to be tailored to peak during the first seconds of flight, then to slowly tail off with time. It turns out that the Ariane 5 ECA booster has roughly the same average thrust as the GSLV Mk3 booster, but the Ariane 5 booster burns longer.

Total propellant mass is not necessarily linearly related to thrust. Thrust is determined by propellant surface area, among other things.

Even if the capability of GSLV-Mk III is 5-GTO and 10-12 to LEO wouldn't a total mass of 630 tons be very high compared to other launch vehicles of the same payload capability

I was quite surprised to see some of the other launch vehicles in this payload category. The GSLV-Mk III weighs in about 630,000 kg.

*The American Delta-IV Medium has a payload capability of 4 tons to GTO and 9 tons to LEO. It weighs at around 250,000 kg

*The European Ariane-4 Heavy(retired) had a capability of 4.5 tons to GTO and 8 tons to LEO. It had a mass of 470,000 kg.

*The Japanese H-II (retired) had a payload capability of 4 tons to GTO and 10 tons to LEO. It's overall mass was surprisingly 260,000 kg

*The Chinese Long March-2E(A) has a capability of about 3.5 tons to GTO and 9 tons to LEO. It's overall mass is 462,000 kg.

What would be the cause of this very high overall mass ?Is GSLV- Mk III so in-efficient ??

GSLV Mk III is projected to weigh about the same as Titan IIIC, which offered roughly similar payload capacity. Both weigh so much because both were/will be equipped with big throat solid rocket motors. Big solid motors are heavier than a comparable liquid stage, but they produce copious amounts of liftoff thrust (the Mk III solid pair produce half again as much thrust as Proton's first stage) and their simplicity is supposed to make them cost less than an equivalent liquid stage.

None of the examples you listed above used solid motors as big and heavy as GSLV Mk III and Titan IIIC. In addition, Delta IV and H-2A use hydrogen-fueled core stages, which provide more energy per kilogram than GSLV's UDMH/N2O4. Note that 480 of the GSLV Mk III 630 tonne liftoff mass is from the Mk III solids.